Low-loss hollow waveguides with periodic claddings, in both fiber and integrated form, are emerging as an important class of optical devices. Potential applications include temperature-insensitive and tunable telecommunication devices, optical analysis of small volumes of gases or liquids, nonlinear optics in gases, novel slow light and opto-mechanical structures, and chip-scale optical interconnects. Integrated hollow waveguides have traditionally been fabricated by wafer bonding or by selective etching of a sacrificial material.